libcamera: thread: Add a messaging passing API

Create a new Message class to model a message that can be passed to an
object living in another thread. Only an invalid message type is
currently defined, more messages will be added in the future.

The Thread class is extended with a messages queue, and the Object class
with thread affinity.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/libcamera/include/thread.h b/src/libcamera/include/thread.h
index e881d90e..acae91cb 100644
--- a/src/libcamera/include/thread.h
+++ b/src/libcamera/include/thread.h
@@ -16,6 +16,8 @@
 namespace libcamera {
 
 class EventDispatcher;
+class Message;
+class Object;
 class ThreadData;
 class ThreadMain;
 
@@ -49,9 +51,16 @@ private:
 	void startThread();
 	void finishThread();
 
+	void postMessage(std::unique_ptr<Message> msg, Object *receiver);
+	void removeMessages(Object *receiver);
+	void dispatchMessages();
+
+	friend class Object;
 	friend class ThreadData;
 	friend class ThreadMain;
 
+	void moveObject(Object *object);
+
 	std::thread thread_;
 	ThreadData *data_;
 };